Improved service method and its positioning performance of the Galileo satellite clock correction

Abstract

The service of the Global Satellite Navigation System (GNSS) satellite clock correction should be provided to achieve a high-precision user positioning. To explore new method for improving the real-time service capability of the Galileo satellite clock correction, its positioning performances of modeling and extrapolation with the polynomial and harmonics-based function are tested. The single point positioning result of the strategy, which employs the 1-h satellite clock correction series to fit the 4-h extrapolation coefficients of 1st order polynomial, is comparable to the current broadcast ephemeris of 10-min age. This shows that the age of the Galileo broadcast ephemeris can be extended. The precise point positioning (PPP) performances of the different extrapolation strategies are analyzed to establish an optimal Galileo real-time service (RTS) strategy, which supports a longer update interval of the transmitted coefficients. The PPP results show that the 6th order polynomial is suitable to establish the RTS of 1- and 2- min update intervals, while that of 2nd order polynomial has the best performance in 5- min interval RTS and the 1st order polynomial is the best one in the 10-min interval RTS. In these RTS strategies, the 1-h satellite clock correction series is optimal to fit the transmitted coefficients.